6533b7d9fe1ef96bd126d646

RESEARCH PRODUCT

Feel the force

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An approach based on quantum sensing, in which controlled quantum systems serve as precision sensors, has enabled measurement of the weak magnetic interaction between two electrons bound to two separate ions. See Letter p.376 Every electron carries an intrinsic magnetic dipole moment, so any two electrons should therefore exert magnetic forces on one another. The forces involved are very small, and at atomic scale Coulomb interaction is dominant, so it is extremely difficult to observe the magnetic interaction. However, Shlomi Kotler et al. have now done just that, measuring the interaction between two electrons, in separate trapped strontium-88 ions. The two electrons exhibit spin entanglement generation over 15 seconds of coherent evolution, and by varying inter-electron separation the authors demonstrate distance dependence that is consistent with the known inverse-cube law.